Windshield wiping device for a motor vehicle

ABSTRACT

Windshield wiper device for a motor vehicle with at least one molded tube ( 10 ) to accommodate a drive shaft to drive at least one wiper arm, wherein the at least one molded tube ( 10 ) can be attached to a holding element ( 11 ) that can be connected to the body, and to a stub ( 12 ) accommodating a mounting plate tube, and connecting bridges ( 14, 15 ) are provided to attach the at least one molded tube ( 10 ) to the holding element ( 11 ) and/or to the stub ( 12 ).

The invention relates to a windshield wiper device for a motor vehiclewith at least one molded tube to accommodate a drive shaft to drive atleast one wiper arm, wherein the at least one molded tube can beattached to a holding element that can be connected to the body, and toa stub accommodating a mounting plate tube.

Pedestrians are completely unprotected in collisions with vehicles. Inparticular, inflexible, hard parts under the engine hood frequently leadto severe injuries when a pedestrian impacts a vehicle. The windshieldwiper device is located in an area where a pedestrian frequently impactsin the case of a collision with a vehicle. In order to minimize the riskof injury, vehicle manufacturers are required to maintain a minimumdistance of 65 to 85 mm between the engine hood and the wiper drive.However, as a rule a drive shaft for the windshield wiper deviceprojects out of the molded tube and normally has only a distance of 10mm to the hood. In a collision, if the head of a pedestrian impacts thearea of the molded tube, the engine hood is only able to deformrelatively little in this area. Consequently, severe injuries to thepedestrian are to be expected. As a result, solutions are known from thestate of the art in which the molded tube breaks due to an impact sothat the risk of injury to the pedestrian is reduced.

DE 696 00 678 T2 describes a wiper device for a motor vehicle with amolded tube to which a holding element and stub are attached. The stubor the holding element features a notch at which the stub or holdingelement break in the case of an impact with a pedestrian. This proposedsolution has the disadvantage, however, that a lot of material ispresent, particularly in the area of the attachment of the holdingelement and the stub to the molded tube. Although a break between theholding element and the molded tube or between the stub and the moldedtube is striven for.

The object of the invention is improving a windshield wiper device ofthe type cited at the outset in such a way that in the future theattachment of the molded tube to the holding element and/or to the stubcan be realized in a manner that saves more material.

The invention attains the imposed objective with a windshield wiperdevice for a motor vehicle with at least one molded tube to accommodatea drive shaft to drive at least one wiper arm, wherein the at least onemolded tube can be attached to a holding element that can be connectedto the body, and to a stub accommodating a mounting plate tube.According to the invention, the windshield wiper device is characterizedin that connecting bridges are provided to attach the at least onemolded tube to the holding element and/or to the stub. The connectingbridges are relatively thin and therefore material-saving parts. As aresult, they serve to reduce weight and costs. The connecting bridgesare structural elements that are simple to realize in terms of design,which, particularly in the case of a plastic design, can be realized inan economical manner in terms of the requirements imposed on them.

Despite this, they guarantee a reliable attachment of the molded tube tothe holding element and to the stub. In addition, the connecting bridgescan deform or break off in the case of a pedestrian impact with theengine hood in such a way that the molded tube is displaced in thedirection of the impact force as a result of the impact. Therefore, themolded tube does not represent a risk of injury to the pedestrian. Inaddition to plastic, zinc and aluminum die casting in particular can beconsidered as construction materials.

In the case of a development of the invention, an impact force acting onthe at least one molded tube and therefore on the connecting bridges canbe strengthened by a lever arm design. Because of the lever arm design,the deforming or breaking off of the connecting bridges is guaranteedeven in the case of small forces, thereby increasing the pedestrian'ssafety.

It is possible to design the lever arm design in such a way that theconnecting bridges are subjected to tension and/or bending over theirentire cross-section when the impact force acts on the molded tube. Theconnecting bridges are especially greatly stressed due to tension loadand/or bending load. Consequently, the connecting bridges can be bent orbroken from the tension and/or bending load even with low forces.

If the windshield wiper device features connecting bridges each of whichhas a different cross-section, the connecting bridges with the smallestcross-section will fail first and then the connecting bridges with thelarger cross-section. As a result, the connecting bridges can break orbend in a sequence that is precisely defined in advance.

In a preferred embodiment of the invention, the connecting bridges canbe arranged like elbow levers. As a result, the great stress can buildup in the connecting bridges even with small deformation paths, wherebythe weaker connecting bridges fail relatively quickly and therebyguarantee continued movement of the at least one molded tube out of theimpact area.

The connecting bridges can also be equipped expediently withpredetermined breaking points in order to also guarantee that theconnecting bridges break in a secure way.

Furthermore, the invention includes a windshield wiper device for amotor vehicle with at least one molded tube to accommodate a drive shaftto drive at least one wiper arm, wherein the at least one molded tubecan be attached to a holding element that can be, connected to the body,and, in accordance with the invention, the holding element features across-section reduction in the area of the attachment of the at leastone molded tube to the holding element. Consequently, even with lowstress the molded tube can be bent or broken together with the holdingelement to which it is attached via an impact in the area of thecross-section reduction.

So that the holding element is bent or breaks reliably in the area ofthe cross-section reduction even with low stress, the cross-sectionreduction can be arranged in the area of a maximum bending moment or amaximum tensile stress.

In addition, it is also possible to select the material thickness of theholding element in such a way that, without a reduction in thecross-section, the holding element bends away or breaks off togetherwith the molded tube in the case of an impact.

Exemplary embodiments will be explained in more detail in the followingon the basis of the enclosed drawings.

In detail, the drawings show:

FIG. 1 A perspective view of a first attachment possibility of a moldedtube with a holding element and a connection piece.

FIG. 2 A perspective view of a second attachment possibility of a moldedtube with a holding element and a connection piece.

FIG. 1 shows a molded tube 10 into which a drive shaft (not shown herein more detail) to drive a wiper arm (also not shown here in moredetail) can be inserted. A holding element 11 and a stub 12 are attachedto the molded tube 10. The holding element 11 features a receptacleopening 13 into which the fastening means (not shown here) for fasteningthe holding element 11 to a body (also not shown here) can beintroduced. A solid point of fixation 17 is created by the connection ofthe holding element 11 to the body. A mounting plate tube (also notshown) can be crimped onto the stub 12 so that the stub 12 features asolid point of fixation 18. The holding element 11 and the stub 12 areconnected to the molded tube 10 via bridges 14 and 15. The bridges 15each feature an elbow 16, which is connected to the molded tube 10. If aforce F, e.g., an impact force in the case of the impact of apedestrian, acts on the molded tube 10, the molded tube 10 then moves inthe direction of force F as a result of force F and as a result of thereaction forces acting on the points of fixation 17 and 18, whereby theelbows 16 are also moved in the direction of force F. Due to themovement of the elbows 16, the connecting bridges 15 are distended sothat the connecting bridges 14 thereby experience a great tension loadand ultimately tear. The connecting bridges 15 also become overloadedbecause of the tearing of the connecting bridges 14. Finally, theconnecting bridges 15 also tear as a result of the bending load actingon them so that the molded tube 10 yields to the impact in the directionof force F.

FIG. 2 shows a molded tube 20 onto which a holding element 21 and a stub22 are attached. The holding element 21 can be fastened on a vehiclebody (not shown in more detail) so that there is a solid point offixation 27. The stub 22 can be crimped onto a mounting plate tube (alsonot shown) so that the stub 22 features a solid point of fixation 28.The holding element 21 is connected to the molded tube 20 via connectingbridges 23 and 24. If an impact force F acts on the molded tube 20,corresponding reaction forces act on the points of fixation 27 and 28.Because of the force F and the reaction forces opposing it, theconnecting bridge 23, which has a smaller cross-section than connectingbridge 24, is subjected very heavily to tension so that it tears asresult of this load. Connecting bridge 24 also ultimately breaks becauseof the overload so that the molded tube 20 yields to the impact in thedirection of the force F. The force F acts with a lever arm h₁ withrespect to point of fixation 27, while the tension force acting on theconnecting bridge 23 acts with lever arm h₂. The greater h₁ is or thesmaller h₂ is, the sooner the connecting bridge 23 tears. As a result, aprecise dimensioning of lever arms h₁ and h₂ can determine the minimumrequired force necessary for the failure of the connecting bridge 23.

1. Windshield wiper device for a motor vehicle with at least one moldedtube (10, 20) to accommodate a drive shaft to drive at least one wiperarm, wherein the at least one molded tube (10, 20) can be attached to aholding element (11, 21) that can be connected to a body, and to a stub(12, 22) accommodating a mounting plate tube, characterized in thatconnecting bridges (14, 15, 23, 24) are provided to attach the at leastone molded tube (10, 20) to at least one of the holding element (11, 21)and the stub (12, 22).
 2. Windshield wiper device according to claim 1,characterized in that an impact force (F) acting on the at least onemolded tube (10, 20) and therefore on the connecting bridges (14, 15,23, 24) is strengthened by a lever arm design.
 3. Windshield wiperdevice according to claim 2, characterized in that the connectingbridges (14, 15, 23, 24) can be subjected to tension and/or bending overtheir entire cross-section via the impact force (F) acting on the leverarm design.
 4. Windshield wiper device according to claim 1,characterized by connecting bridges (14, 15, 23, 24) each of which has adifferent cross-section.
 5. Windshield wiper device according to claim2, characterized in that connecting bridges (15) are arranged like elbowlevers.
 6. Windshield wiper device according to claim 1, characterizedin that the connecting bridges (14, 15, 23, 24) feature predeterminedbreaking points.
 7. Windshield wiper device for a motor vehicle with atleast one molded tube to accommodate a drive shaft to drive at least onewiper arm, wherein the at least one molded tube can be attached to aholding element that can be connected to the body, characterized in thatthe holding element features a cross-section reduction in the area ofthe attachment of the at least one molded tube to the holding element.8. Windshield wiper device according to claim 7, characterized in thatthe cross-section reduction is located in the area of a maximum bendingmoment or a maximum tensile stress.
 9. Windshield wiper device accordingto claim 1, wherein the connecting bridges attach the molded tube to theholding element.
 10. Windshield wiper device according to claim 1,wherein the connecting bridges attach the molded tube to the stub. 11.Windshield wiper device according to claim 1, wherein the connectingbridges attach the molded tube to both the holding element and the stub.12. Windshield wiper device according to claim 3, characterized byconnecting bridges (14, 15, 23, 24) each of which has a differentcross-section.
 13. Windshield wiper device according to claim 12,characterized in that connecting bridges (15) are arranged like elbowlevers.
 14. Windshield wiper device according to claim 13, characterizedin that the connecting bridges (14, 15, 23, 24) feature predeterminedbreaking points.
 15. Windshield wiper device according to claim 5,characterized in that the connecting bridges (14, 15, 23, 24) featurepredetermined breaking points.
 16. A windshield wiper device for a motorvehicle with at least one molded tube for receiving a drive shaftadapted to drive at least one wiper arm, the molded tube being attachedto a holding element that can be connected to a body, and the moldedtube being attached to a stub connectable to a mounting plate tube, themolded tube being attached to the holding element and to the stub byconnecting bridges formed so that the connecting bridges tear in theevent of an impact force.
 17. A windshield wiper device according toclaim 16, wherein the impact force is strengthened by a lever arm designof a connecting lever.
 18. A windshield wiper device according to claim17, wherein the connecting bridges are formed as elbow levers.
 19. Awindshield wiper device according to claim 16, wherein each of theconnecting levers has a different cross-section.
 20. A windshield wiperdevice according to claim 16, wherein the connecting bridges havepredetermined breaking points.